Peripherally vented couch roll



SePt- 20, 1955 L.. HoRNBosTEL l 2,718,180

PERIPHERALLY VENTED COUCH ROLL Filed DSC. 8, 1950 FJ .4 j@ 171 5 171 1519 1y fUVEJ-J D11-f jagd 502721905239;

by #12571 H7; g5

United States Patent O 'PERIPHERALLY vENTED coUcH ROLL Lloyd Hornhostel, Beloit, Wis., ass'iignor to Beloit Iron Works, Beloit,'Wis., acorporation of Wisconsin I Application December .8, 1950, Serial No. 199,866

1 Claim. (Cl.-92-4"7) 'The present'invention relates 'to a peripherally vented paper Imachine roll :and more particularly to a peripherally vented couch roll for a paper making machine for facil'itating the smooth, rapid transfer of a moist paper we'b :from a forming wire to a pickup felt.

'The present 'invention is particularly adaptable for use with pickup felt-type paper making machines, such as are used for making light Weight tissues and simi-lar p'apers. A particularly vexing problem in this type of machine has been the transfer of the relatively light weight paper web from a machine forming surface to a pickup felt. Upon pulling the paper web from the surface of Athe for-ming wire as the forming wire is supported upon the -couch roll, a vacuum is formed between thecouch roll shell, the forming wire surface, and the paper web, this vacuum resisting smooth transfer of the web to the pickup felt.

Various forms of couch rolls have been proposed -in the ,prior art for eliminating transfer diiiiculties atthe couch roll, the most conventional couch roll beingof the suction type. The suction couch roll generally includes a perforated rotatable shell provided with means defining peripheral compartments enclosing the outer surface of the perforate drum and communicating with a suction gland in the interior of the drum through the drum perforations. Upon evacuation of the suction gland, air is drawn into the peripheral compartments through the paper machine kforming wire itself to break any vacuum which might exist between the moist paper web, the forming wire and the couch roll. One of the primary disadvantages residing in the utilization of a vacuum couch roll is the expense of radially perforating the rotatable shell by precision drilling methods, and the necessity of providing expensive suction gland evacuating equipment.

The present invention provides a peripherally vented couch roll wherein an imperforate roll shell is utilized and in which it is not necessary to provide shell evacuating means for drawing air into the roll periphery. More particularly, the present invention comprises, in general, an imperforate rotatable shell having peripheral radial tins extending axially of the roll to define a plurality of adjacent compartments at the roll outer periphery. The roll peripheral surface is foraminous and is preferably provided by a plurality of spirally wound wires which circumferentially overlie the compartments. The compartments communicate with one another and with the atmosphere through transversely extending apertures formed in each of the radial tins, so that the compartments are peripherally vented to one another. lt will be seen that, upon removal of a moist paper web from the surface of the roll or from a forming wire trained thereabout, any vacuum which could be formed in the compartments would be vented to atmosphere pressure conditions through adjacent compartments not covered by the moist paper Web.

It is, therefore, an important object of the present in- Patented sept. 2o, 1955 2 vention to provide a peripherally ventedjweb transfer roll vfor a lpaper `making machine.

Another important object of the present invention is to provide a paper making machine Acou-ch roll Aincluding Aa circumferentially compartmented, imperforate roll shell 4which vis provided with means for venting -the shell periphery 'to the atmosphere to *break a vacuum formed at the shell periphery during machine operation.

It is a further important object yof the present i-nvention to provide -a .paper making -machine wherein a forming wire is lapped about a peripherally vented couch roll for coaction with a pickup felt to remove a vmoist paper web from the formi-ng wire, the Iperipheral ventingr of the couch roll kpreventing :the formation of a vacuum fbetween the moist paper web, the forming wire, :and the couch roll.

Still another important object of the present' invention is the provision of a peripherally vented suction couch roll including an imperforate roll shell, and a plurality of radial iins carried by the shell to extend axially thereof to define adjacent peripheral compartments, ythe roll surface being dened by a rspira'lly '-wound wire carried by .the tins vand overlying the compartments, and the compartments communicating with one another through lin apertures to establish :fluid .pressure communication between the various-=compartments for preventing the vformation of a vacuum within thefcompartments during 1machine operation.

`Other yand vfurther :important objects of this invention will be apparent from the disclosures inthe specification and the `accompanying drawings.

ln the drawings:

Figure l is a fragmentary, somewhat schematic illustration of a papermaking machine provided with a paper machinefroll of the present invention-lapped by a form, ing'ywire coacting with a pickup felt;

Figure 2 is a greatly enlarged, fragmentary, elevational view of a kportion of .the foraminous periphery of thetroll of Figure l;

Figure 3 is a greatly enlarged sectional view taken along the plane 1li-Ill of Figure 2; and Figure 4 fis a ,sectional view taken along the plane lV-IV of Figure 3.

As shown on the drawings:

In Figure l, reference numeral 10 refers generally to a roll of the present invention utilized as a couch roll of a Fourdrinier-type paper making machine and lapped by a foraminous forming wire 11 of the paper machine bearing on its upper surface a moist paper web W formed by the deposition of paper pulp fibers on the forming wire 11, as is well known in the art.

A pickup felt 12 is trained about a pickup roll 13 into contact with the web W as the web is supported upon the forming wire 11 at the periphery of the roll 10. The pickup felt 12 serves to pickup the moist paper web W from the forming wire 11 and to convey the same to later portions of the paper machine press part or the like. An arcuate saveall pan 14 is positioned adjacent the roll 10 to receive water flung centrifugally from the roll and the wire 11 during rotation of the roll.

The construction of the roll 10 is shown in Figures 2-4, inclusive, the roll including an imperforate, generally cylindrical roll shell 15, the roll shell being journaled at'its axial ends for rotation about a substantially horizontal axis. The outer periphery of the shell 15 is provided with a series of substantially parallel, elongated, axially extending grooves 16, and within each groove there is seated an elongated geenrally rectangular roll iin or rib 17. Each of the ns 17 extends along the entire axial length of the roll. Those portions 17a of each of the iins within the grooves 16 are secured therein by suitable means, as by swaging, Welding, soldering or the like.

The ns 17 are thus provided to extend radially outwardly from the outer periphery 15a of the roll shell 15, the fins cooperating to define individual circumferential compartments 18 about the roll periphery. The compartments 18 are in communication with one another through apertures 17b, which are spaced along the length of each of the ins 17.

The surface roll 10 is provided by winding wire or strips 19 which are ush with the outer pin surfaces and seated within notches 17C formed in each of the iins 17 along the length thereof. The notches 17e` are so formed that a single continuous strip passing through the notches of the series of fins 17 about the periphery of the roll will be formed to a spiral configuration as best seen in Figure 2. Of course, it will be appreciated that a plurality of separate winding wires or strips 19 are preferably utilized toform a foraminous, open surface of the roll overlying and fully communicating with the compartments 18 dened by the fins 17 and the roll 15.

It will be seen that upon removing the moist paper web W from a surface of the roll 10, any tendency toward forming a partial vacuum within the chamber 18 immediately underlying that portion of the web being removed from the forming wire will be obviated by air at atmospheric pressure entering the given compartment from adjacent uncovered compartments through the apertures 17b. In this manner, the entire periphery of the roll 10 is constantly vented to circumambient atmospheric pressures, the circumferential compartments 18 are in constant fluid pressure communication with one another and with the atmosphere, and it is impossible to form even a local sub-atmospheric pressure area under any machine operating conditions.

Those skilled in the art will readily appreciate the desirability of the present invention inasmuch as the instant structure eliminates the heretofore necessary apertured or perforated roll drums, thereby greatly reducing the cost of the roll 10. In addition to a reduction in the cost of the roll itself, it is not necessary in the present invention to provide the heretofore necessary auxiliary vacuum equipment for evacuating the interior of the perforated drum. The advantages which are provided by the constant peripheral Venting of the roll to atmospheric pressures result in the freeing of the moist paper web W from the wire 11 with the least amount of effort even at relatively great web speeds, and without danger of tearing or otherwise damaging the sheet during its removal.

It will be understood that modifications and variations may be effected without departing from the scope of the novel concepts of the present invention.

l claim as my invention:

In a paper making machine, a couch roll comprising an imporforate rotatable shell, a plurality of elongated fins aligned parallel to the axis of the roll carried by said shell and projecting outwardly from and around the periphery thereof to form peripheral compartments therewith, notches in the upper surface 0f said iins spaced along the length thereof, and helicaJly wound wire in said notches to define a foraminous roll surface substantially ush with the outwardly projecting n surfaces, said ns being apertured along their lengths to establish fluid pressure communication between said compartments, a foraminous forming Wire trained about said roll surface and adapted to carry a paper Aweb 'l thereon, and a pickup felt contacting said wire supported on said roll to remove said web therefrom, the communication of said compartments with one another accommodating the low of air therebetween to break any vacuum at the roll surface as the web is removed from said forming wire.

References Cited in the le of this patent UNITED STATES PATENTS 196,634 Cornell Oct. 30, 1877 232,031 Henry Sept. 7, 1880 345,274 Browne July 13, 1886 412,359 Boyne Oct. 8, 1889 631,106 Crocker et al. Aug. 5, 1899 693,894 Parker Feb. 25, 1902 1,100,090 Parker June 16, 1914 1,783,868 Wenzel Dec. 2, 1930 `1,814,864 Sinclair July 14, 1931 1,915,759 Plank June 27, 1933 2,065,263 Beldam 'Dec. 22, 1936 2,443,352 Hornbostel June 15, 1948 FOREIGN PATENTS 542,118 Germany' Ian. 20, 1932 

